1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2015, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
28 with Debug; use Debug;
29 with Einfo; use Einfo;
30 with Elists; use Elists;
31 with Nlists; use Nlists;
32 with Errout; use Errout;
34 with Namet; use Namet;
36 with Output; use Output;
38 with Sem_Aux; use Sem_Aux;
39 with Sem_Ch6; use Sem_Ch6;
40 with Sem_Ch8; use Sem_Ch8;
41 with Sem_Ch12; use Sem_Ch12;
42 with Sem_Disp; use Sem_Disp;
43 with Sem_Dist; use Sem_Dist;
44 with Sem_Util; use Sem_Util;
45 with Stand; use Stand;
46 with Sinfo; use Sinfo;
47 with Snames; use Snames;
49 with Treepr; use Treepr;
50 with Uintp; use Uintp;
52 package body Sem_Type is
58 -- The following data structures establish a mapping between nodes and
59 -- their interpretations. An overloaded node has an entry in Interp_Map,
60 -- which in turn contains a pointer into the All_Interp array. The
61 -- interpretations of a given node are contiguous in All_Interp. Each set
62 -- of interpretations is terminated with the marker No_Interp. In order to
63 -- speed up the retrieval of the interpretations of an overloaded node, the
64 -- Interp_Map table is accessed by means of a simple hashing scheme, and
65 -- the entries in Interp_Map are chained. The heads of clash lists are
66 -- stored in array Headers.
68 -- Headers Interp_Map All_Interp
70 -- _ +-----+ +--------+
71 -- |_| |_____| --->|interp1 |
72 -- |_|---------->|node | | |interp2 |
73 -- |_| |index|---------| |nointerp|
78 -- This scheme does not currently reclaim interpretations. In principle,
79 -- after a unit is compiled, all overloadings have been resolved, and the
80 -- candidate interpretations should be deleted. This should be easier
81 -- now than with the previous scheme???
83 package All_Interp is new Table.Table (
84 Table_Component_Type => Interp,
85 Table_Index_Type => Interp_Index,
87 Table_Initial => Alloc.All_Interp_Initial,
88 Table_Increment => Alloc.All_Interp_Increment,
89 Table_Name => "All_Interp");
91 type Interp_Ref is record
97 Header_Size : constant Int := 2 ** 12;
98 No_Entry : constant Int := -1;
99 Headers : array (0 .. Header_Size) of Int := (others => No_Entry);
101 package Interp_Map is new Table.Table (
102 Table_Component_Type => Interp_Ref,
103 Table_Index_Type => Int,
104 Table_Low_Bound => 0,
105 Table_Initial => Alloc.Interp_Map_Initial,
106 Table_Increment => Alloc.Interp_Map_Increment,
107 Table_Name => "Interp_Map");
109 function Hash (N : Node_Id) return Int;
110 -- A trivial hashing function for nodes, used to insert an overloaded
111 -- node into the Interp_Map table.
113 -------------------------------------
114 -- Handling of Overload Resolution --
115 -------------------------------------
117 -- Overload resolution uses two passes over the syntax tree of a complete
118 -- context. In the first, bottom-up pass, the types of actuals in calls
119 -- are used to resolve possibly overloaded subprogram and operator names.
120 -- In the second top-down pass, the type of the context (for example the
121 -- condition in a while statement) is used to resolve a possibly ambiguous
122 -- call, and the unique subprogram name in turn imposes a specific context
123 -- on each of its actuals.
125 -- Most expressions are in fact unambiguous, and the bottom-up pass is
126 -- sufficient to resolve most everything. To simplify the common case,
127 -- names and expressions carry a flag Is_Overloaded to indicate whether
128 -- they have more than one interpretation. If the flag is off, then each
129 -- name has already a unique meaning and type, and the bottom-up pass is
130 -- sufficient (and much simpler).
132 --------------------------
133 -- Operator Overloading --
134 --------------------------
136 -- The visibility of operators is handled differently from that of other
137 -- entities. We do not introduce explicit versions of primitive operators
138 -- for each type definition. As a result, there is only one entity
139 -- corresponding to predefined addition on all numeric types, etc. The
140 -- back-end resolves predefined operators according to their type. The
141 -- visibility of primitive operations then reduces to the visibility of the
142 -- resulting type: (a + b) is a legal interpretation of some primitive
143 -- operator + if the type of the result (which must also be the type of a
144 -- and b) is directly visible (either immediately visible or use-visible).
146 -- User-defined operators are treated like other functions, but the
147 -- visibility of these user-defined operations must be special-cased
148 -- to determine whether they hide or are hidden by predefined operators.
149 -- The form P."+" (x, y) requires additional handling.
151 -- Concatenation is treated more conventionally: for every one-dimensional
152 -- array type we introduce a explicit concatenation operator. This is
153 -- necessary to handle the case of (element & element => array) which
154 -- cannot be handled conveniently if there is no explicit instance of
155 -- resulting type of the operation.
157 -----------------------
158 -- Local Subprograms --
159 -----------------------
161 procedure All_Overloads;
162 pragma Warnings (Off, All_Overloads);
163 -- Debugging procedure: list full contents of Overloads table
165 function Binary_Op_Interp_Has_Abstract_Op
167 E : Entity_Id) return Entity_Id;
168 -- Given the node and entity of a binary operator, determine whether the
169 -- actuals of E contain an abstract interpretation with regards to the
170 -- types of their corresponding formals. Return the abstract operation or
173 function Function_Interp_Has_Abstract_Op
175 E : Entity_Id) return Entity_Id;
176 -- Given the node and entity of a function call, determine whether the
177 -- actuals of E contain an abstract interpretation with regards to the
178 -- types of their corresponding formals. Return the abstract operation or
181 function Has_Abstract_Op
183 Typ : Entity_Id) return Entity_Id;
184 -- Subsidiary routine to Binary_Op_Interp_Has_Abstract_Op and Function_
185 -- Interp_Has_Abstract_Op. Determine whether an overloaded node has an
186 -- abstract interpretation which yields type Typ.
188 procedure New_Interps (N : Node_Id);
189 -- Initialize collection of interpretations for the given node, which is
190 -- either an overloaded entity, or an operation whose arguments have
191 -- multiple interpretations. Interpretations can be added to only one
194 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id;
195 -- If Typ_1 and Typ_2 are compatible, return the one that is not universal
196 -- or is not a "class" type (any_character, etc).
202 procedure Add_One_Interp
206 Opnd_Type : Entity_Id := Empty)
208 Vis_Type : Entity_Id;
210 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id);
211 -- Add one interpretation to an overloaded node. Add a new entry if
212 -- not hidden by previous one, and remove previous one if hidden by
215 function Is_Universal_Operation (Op : Entity_Id) return Boolean;
216 -- True if the entity is a predefined operator and the operands have
217 -- a universal Interpretation.
223 procedure Add_Entry (Name : Entity_Id; Typ : Entity_Id) is
224 Abstr_Op : Entity_Id := Empty;
228 -- Start of processing for Add_Entry
231 -- Find out whether the new entry references interpretations that
232 -- are abstract or disabled by abstract operators.
234 if Ada_Version >= Ada_2005 then
235 if Nkind (N) in N_Binary_Op then
236 Abstr_Op := Binary_Op_Interp_Has_Abstract_Op (N, Name);
237 elsif Nkind (N) = N_Function_Call then
238 Abstr_Op := Function_Interp_Has_Abstract_Op (N, Name);
242 Get_First_Interp (N, I, It);
243 while Present (It.Nam) loop
245 -- A user-defined subprogram hides another declared at an outer
246 -- level, or one that is use-visible. So return if previous
247 -- definition hides new one (which is either in an outer
248 -- scope, or use-visible). Note that for functions use-visible
249 -- is the same as potentially use-visible. If new one hides
250 -- previous one, replace entry in table of interpretations.
251 -- If this is a universal operation, retain the operator in case
252 -- preference rule applies.
254 if (((Ekind (Name) = E_Function or else Ekind (Name) = E_Procedure)
255 and then Ekind (Name) = Ekind (It.Nam))
256 or else (Ekind (Name) = E_Operator
257 and then Ekind (It.Nam) = E_Function))
258 and then Is_Immediately_Visible (It.Nam)
259 and then Type_Conformant (Name, It.Nam)
260 and then Base_Type (It.Typ) = Base_Type (T)
262 if Is_Universal_Operation (Name) then
265 -- If node is an operator symbol, we have no actuals with
266 -- which to check hiding, and this is done in full in the
267 -- caller (Analyze_Subprogram_Renaming) so we include the
268 -- predefined operator in any case.
270 elsif Nkind (N) = N_Operator_Symbol
272 (Nkind (N) = N_Expanded_Name
273 and then Nkind (Selector_Name (N)) = N_Operator_Symbol)
277 elsif not In_Open_Scopes (Scope (Name))
278 or else Scope_Depth (Scope (Name)) <=
279 Scope_Depth (Scope (It.Nam))
281 -- If ambiguity within instance, and entity is not an
282 -- implicit operation, save for later disambiguation.
284 if Scope (Name) = Scope (It.Nam)
285 and then not Is_Inherited_Operation (Name)
294 All_Interp.Table (I).Nam := Name;
298 -- Avoid making duplicate entries in overloads
301 and then Base_Type (It.Typ) = Base_Type (T)
305 -- Otherwise keep going
308 Get_Next_Interp (I, It);
313 All_Interp.Table (All_Interp.Last) := (Name, Typ, Abstr_Op);
314 All_Interp.Append (No_Interp);
317 ----------------------------
318 -- Is_Universal_Operation --
319 ----------------------------
321 function Is_Universal_Operation (Op : Entity_Id) return Boolean is
325 if Ekind (Op) /= E_Operator then
328 elsif Nkind (N) in N_Binary_Op then
329 return Present (Universal_Interpretation (Left_Opnd (N)))
330 and then Present (Universal_Interpretation (Right_Opnd (N)));
332 elsif Nkind (N) in N_Unary_Op then
333 return Present (Universal_Interpretation (Right_Opnd (N)));
335 elsif Nkind (N) = N_Function_Call then
336 Arg := First_Actual (N);
337 while Present (Arg) loop
338 if No (Universal_Interpretation (Arg)) then
350 end Is_Universal_Operation;
352 -- Start of processing for Add_One_Interp
355 -- If the interpretation is a predefined operator, verify that the
356 -- result type is visible, or that the entity has already been
357 -- resolved (case of an instantiation node that refers to a predefined
358 -- operation, or an internally generated operator node, or an operator
359 -- given as an expanded name). If the operator is a comparison or
360 -- equality, it is the type of the operand that matters to determine
361 -- whether the operator is visible. In an instance, the check is not
362 -- performed, given that the operator was visible in the generic.
364 if Ekind (E) = E_Operator then
365 if Present (Opnd_Type) then
366 Vis_Type := Opnd_Type;
368 Vis_Type := Base_Type (T);
371 if In_Open_Scopes (Scope (Vis_Type))
372 or else Is_Potentially_Use_Visible (Vis_Type)
373 or else In_Use (Vis_Type)
374 or else (In_Use (Scope (Vis_Type))
375 and then not Is_Hidden (Vis_Type))
376 or else Nkind (N) = N_Expanded_Name
377 or else (Nkind (N) in N_Op and then E = Entity (N))
379 or else Ekind (Vis_Type) = E_Anonymous_Access_Type
383 -- If the node is given in functional notation and the prefix
384 -- is an expanded name, then the operator is visible if the
385 -- prefix is the scope of the result type as well. If the
386 -- operator is (implicitly) defined in an extension of system,
387 -- it is know to be valid (see Defined_In_Scope, sem_ch4.adb).
389 elsif Nkind (N) = N_Function_Call
390 and then Nkind (Name (N)) = N_Expanded_Name
391 and then (Entity (Prefix (Name (N))) = Scope (Base_Type (T))
392 or else Entity (Prefix (Name (N))) = Scope (Vis_Type)
393 or else Scope (Vis_Type) = System_Aux_Id)
397 -- Save type for subsequent error message, in case no other
398 -- interpretation is found.
401 Candidate_Type := Vis_Type;
405 -- In an instance, an abstract non-dispatching operation cannot be a
406 -- candidate interpretation, because it could not have been one in the
407 -- generic (it may be a spurious overloading in the instance).
410 and then Is_Overloadable (E)
411 and then Is_Abstract_Subprogram (E)
412 and then not Is_Dispatching_Operation (E)
416 -- An inherited interface operation that is implemented by some derived
417 -- type does not participate in overload resolution, only the
418 -- implementation operation does.
421 and then Is_Subprogram (E)
422 and then Present (Interface_Alias (E))
424 -- Ada 2005 (AI-251): If this primitive operation corresponds with
425 -- an immediate ancestor interface there is no need to add it to the
426 -- list of interpretations. The corresponding aliased primitive is
427 -- also in this list of primitive operations and will be used instead
428 -- because otherwise we have a dummy ambiguity between the two
429 -- subprograms which are in fact the same.
432 (Find_Dispatching_Type (Interface_Alias (E)),
433 Find_Dispatching_Type (E))
435 Add_One_Interp (N, Interface_Alias (E), T);
440 -- Calling stubs for an RACW operation never participate in resolution,
441 -- they are executed only through dispatching calls.
443 elsif Is_RACW_Stub_Type_Operation (E) then
447 -- If this is the first interpretation of N, N has type Any_Type.
448 -- In that case place the new type on the node. If one interpretation
449 -- already exists, indicate that the node is overloaded, and store
450 -- both the previous and the new interpretation in All_Interp. If
451 -- this is a later interpretation, just add it to the set.
453 if Etype (N) = Any_Type then
458 -- Record both the operator or subprogram name, and its type
460 if Nkind (N) in N_Op or else Is_Entity_Name (N) then
467 -- Either there is no current interpretation in the table for any
468 -- node or the interpretation that is present is for a different
469 -- node. In both cases add a new interpretation to the table.
471 elsif Interp_Map.Last < 0
473 (Interp_Map.Table (Interp_Map.Last).Node /= N
474 and then not Is_Overloaded (N))
478 if (Nkind (N) in N_Op or else Is_Entity_Name (N))
479 and then Present (Entity (N))
481 Add_Entry (Entity (N), Etype (N));
483 elsif Nkind (N) in N_Subprogram_Call
484 and then Is_Entity_Name (Name (N))
486 Add_Entry (Entity (Name (N)), Etype (N));
488 -- If this is an indirect call there will be no name associated
489 -- with the previous entry. To make diagnostics clearer, save
490 -- Subprogram_Type of first interpretation, so that the error will
491 -- point to the anonymous access to subprogram, not to the result
492 -- type of the call itself.
494 elsif (Nkind (N)) = N_Function_Call
495 and then Nkind (Name (N)) = N_Explicit_Dereference
496 and then Is_Overloaded (Name (N))
502 pragma Warnings (Off, Itn);
505 Get_First_Interp (Name (N), Itn, It);
506 Add_Entry (It.Nam, Etype (N));
510 -- Overloaded prefix in indexed or selected component, or call
511 -- whose name is an expression or another call.
513 Add_Entry (Etype (N), Etype (N));
527 procedure All_Overloads is
529 for J in All_Interp.First .. All_Interp.Last loop
531 if Present (All_Interp.Table (J).Nam) then
532 Write_Entity_Info (All_Interp.Table (J). Nam, " ");
534 Write_Str ("No Interp");
538 Write_Str ("=================");
543 --------------------------------------
544 -- Binary_Op_Interp_Has_Abstract_Op --
545 --------------------------------------
547 function Binary_Op_Interp_Has_Abstract_Op
549 E : Entity_Id) return Entity_Id
551 Abstr_Op : Entity_Id;
552 E_Left : constant Node_Id := First_Formal (E);
553 E_Right : constant Node_Id := Next_Formal (E_Left);
556 Abstr_Op := Has_Abstract_Op (Left_Opnd (N), Etype (E_Left));
557 if Present (Abstr_Op) then
561 return Has_Abstract_Op (Right_Opnd (N), Etype (E_Right));
562 end Binary_Op_Interp_Has_Abstract_Op;
564 ---------------------
565 -- Collect_Interps --
566 ---------------------
568 procedure Collect_Interps (N : Node_Id) is
569 Ent : constant Entity_Id := Entity (N);
571 First_Interp : Interp_Index;
573 function Within_Instance (E : Entity_Id) return Boolean;
574 -- Within an instance there can be spurious ambiguities between a local
575 -- entity and one declared outside of the instance. This can only happen
576 -- for subprograms, because otherwise the local entity hides the outer
577 -- one. For an overloadable entity, this predicate determines whether it
578 -- is a candidate within the instance, or must be ignored.
580 ---------------------
581 -- Within_Instance --
582 ---------------------
584 function Within_Instance (E : Entity_Id) return Boolean is
589 if not In_Instance then
593 Inst := Current_Scope;
594 while Present (Inst) and then not Is_Generic_Instance (Inst) loop
595 Inst := Scope (Inst);
599 while Present (Scop) and then Scop /= Standard_Standard loop
604 Scop := Scope (Scop);
610 -- Start of processing for Collect_Interps
615 -- Unconditionally add the entity that was initially matched
617 First_Interp := All_Interp.Last;
618 Add_One_Interp (N, Ent, Etype (N));
620 -- For expanded name, pick up all additional entities from the
621 -- same scope, since these are obviously also visible. Note that
622 -- these are not necessarily contiguous on the homonym chain.
624 if Nkind (N) = N_Expanded_Name then
626 while Present (H) loop
627 if Scope (H) = Scope (Entity (N)) then
628 Add_One_Interp (N, H, Etype (H));
634 -- Case of direct name
637 -- First, search the homonym chain for directly visible entities
639 H := Current_Entity (Ent);
640 while Present (H) loop
641 exit when (not Is_Overloadable (H))
642 and then Is_Immediately_Visible (H);
644 if Is_Immediately_Visible (H) and then H /= Ent then
646 -- Only add interpretation if not hidden by an inner
647 -- immediately visible one.
649 for J in First_Interp .. All_Interp.Last - 1 loop
651 -- Current homograph is not hidden. Add to overloads
653 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
656 -- Homograph is hidden, unless it is a predefined operator
658 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
660 -- A homograph in the same scope can occur within an
661 -- instantiation, the resulting ambiguity has to be
662 -- resolved later. The homographs may both be local
663 -- functions or actuals, or may be declared at different
664 -- levels within the instance. The renaming of an actual
665 -- within the instance must not be included.
667 if Within_Instance (H)
668 and then H /= Renamed_Entity (Ent)
669 and then not Is_Inherited_Operation (H)
671 All_Interp.Table (All_Interp.Last) :=
672 (H, Etype (H), Empty);
673 All_Interp.Append (No_Interp);
676 elsif Scope (H) /= Standard_Standard then
682 -- On exit, we know that current homograph is not hidden
684 Add_One_Interp (N, H, Etype (H));
687 Write_Str ("Add overloaded interpretation ");
697 -- Scan list of homographs for use-visible entities only
699 H := Current_Entity (Ent);
701 while Present (H) loop
702 if Is_Potentially_Use_Visible (H)
704 and then Is_Overloadable (H)
706 for J in First_Interp .. All_Interp.Last - 1 loop
708 if not Is_Immediately_Visible (All_Interp.Table (J).Nam) then
711 elsif Type_Conformant (H, All_Interp.Table (J).Nam) then
712 goto Next_Use_Homograph;
716 Add_One_Interp (N, H, Etype (H));
719 <<Next_Use_Homograph>>
724 if All_Interp.Last = First_Interp + 1 then
726 -- The final interpretation is in fact not overloaded. Note that the
727 -- unique legal interpretation may or may not be the original one,
728 -- so we need to update N's entity and etype now, because once N
729 -- is marked as not overloaded it is also expected to carry the
730 -- proper interpretation.
732 Set_Is_Overloaded (N, False);
733 Set_Entity (N, All_Interp.Table (First_Interp).Nam);
734 Set_Etype (N, All_Interp.Table (First_Interp).Typ);
742 function Covers (T1, T2 : Entity_Id) return Boolean is
746 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean;
747 -- In an instance the proper view may not always be correct for
748 -- private types, but private and full view are compatible. This
749 -- removes spurious errors from nested instantiations that involve,
750 -- among other things, types derived from private types.
752 function Real_Actual (T : Entity_Id) return Entity_Id;
753 -- If an actual in an inner instance is the formal of an enclosing
754 -- generic, the actual in the enclosing instance is the one that can
755 -- create an accidental ambiguity, and the check on compatibily of
756 -- generic actual types must use this enclosing actual.
758 ----------------------
759 -- Full_View_Covers --
760 ----------------------
762 function Full_View_Covers (Typ1, Typ2 : Entity_Id) return Boolean is
765 Is_Private_Type (Typ1)
767 ((Present (Full_View (Typ1))
768 and then Covers (Full_View (Typ1), Typ2))
769 or else (Present (Underlying_Full_View (Typ1))
770 and then Covers (Underlying_Full_View (Typ1), Typ2))
771 or else Base_Type (Typ1) = Typ2
772 or else Base_Type (Typ2) = Typ1);
773 end Full_View_Covers;
779 function Real_Actual (T : Entity_Id) return Entity_Id is
780 Par : constant Node_Id := Parent (T);
784 -- Retrieve parent subtype from subtype declaration for actual
786 if Nkind (Par) = N_Subtype_Declaration
787 and then not Comes_From_Source (Par)
788 and then Is_Entity_Name (Subtype_Indication (Par))
790 RA := Entity (Subtype_Indication (Par));
792 if Is_Generic_Actual_Type (RA) then
797 -- Otherwise actual is not the actual of an enclosing instance
802 -- Start of processing for Covers
805 -- If either operand missing, then this is an error, but ignore it (and
806 -- pretend we have a cover) if errors already detected, since this may
807 -- simply mean we have malformed trees or a semantic error upstream.
809 if No (T1) or else No (T2) then
810 if Total_Errors_Detected /= 0 then
817 -- Trivial case: same types are always compatible
823 -- First check for Standard_Void_Type, which is special. Subsequent
824 -- processing in this routine assumes T1 and T2 are bona fide types;
825 -- Standard_Void_Type is a special entity that has some, but not all,
826 -- properties of types.
828 if (T1 = Standard_Void_Type) /= (T2 = Standard_Void_Type) then
832 BT1 := Base_Type (T1);
833 BT2 := Base_Type (T2);
835 -- Handle underlying view of records with unknown discriminants
836 -- using the original entity that motivated the construction of
837 -- this underlying record view (see Build_Derived_Private_Type).
839 if Is_Underlying_Record_View (BT1) then
840 BT1 := Underlying_Record_View (BT1);
843 if Is_Underlying_Record_View (BT2) then
844 BT2 := Underlying_Record_View (BT2);
847 -- Simplest case: types that have the same base type and are not generic
848 -- actuals are compatible. Generic actuals belong to their class but are
849 -- not compatible with other types of their class, and in particular
850 -- with other generic actuals. They are however compatible with their
851 -- own subtypes, and itypes with the same base are compatible as well.
852 -- Similarly, constrained subtypes obtained from expressions of an
853 -- unconstrained nominal type are compatible with the base type (may
854 -- lead to spurious ambiguities in obscure cases ???)
856 -- Generic actuals require special treatment to avoid spurious ambi-
857 -- guities in an instance, when two formal types are instantiated with
858 -- the same actual, so that different subprograms end up with the same
859 -- signature in the instance. If a generic actual is the actual of an
860 -- enclosing instance, it is that actual that we must compare: generic
861 -- actuals are only incompatible if they appear in the same instance.
867 if not Is_Generic_Actual_Type (T1)
869 not Is_Generic_Actual_Type (T2)
873 -- Both T1 and T2 are generic actual types
877 RT1 : constant Entity_Id := Real_Actual (T1);
878 RT2 : constant Entity_Id := Real_Actual (T2);
881 or else Is_Itype (T1)
882 or else Is_Itype (T2)
883 or else Is_Constr_Subt_For_U_Nominal (T1)
884 or else Is_Constr_Subt_For_U_Nominal (T2)
885 or else Scope (RT1) /= Scope (RT2);
889 -- Literals are compatible with types in a given "class"
891 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
892 or else (T2 = Universal_Real and then Is_Real_Type (T1))
893 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
894 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
895 or else (T2 = Any_String and then Is_String_Type (T1))
896 or else (T2 = Any_Character and then Is_Character_Type (T1))
897 or else (T2 = Any_Access and then Is_Access_Type (T1))
901 -- The context may be class wide, and a class-wide type is compatible
902 -- with any member of the class.
904 elsif Is_Class_Wide_Type (T1)
905 and then Is_Ancestor (Root_Type (T1), T2)
909 elsif Is_Class_Wide_Type (T1)
910 and then Is_Class_Wide_Type (T2)
911 and then Base_Type (Etype (T1)) = Base_Type (Etype (T2))
915 -- Ada 2005 (AI-345): A class-wide abstract interface type covers a
916 -- task_type or protected_type that implements the interface.
918 elsif Ada_Version >= Ada_2005
919 and then Is_Class_Wide_Type (T1)
920 and then Is_Interface (Etype (T1))
921 and then Is_Concurrent_Type (T2)
922 and then Interface_Present_In_Ancestor
923 (Typ => BT2, Iface => Etype (T1))
927 -- Ada 2005 (AI-251): A class-wide abstract interface type T1 covers an
928 -- object T2 implementing T1.
930 elsif Ada_Version >= Ada_2005
931 and then Is_Class_Wide_Type (T1)
932 and then Is_Interface (Etype (T1))
933 and then Is_Tagged_Type (T2)
935 if Interface_Present_In_Ancestor (Typ => T2,
946 if Is_Concurrent_Type (BT2) then
947 E := Corresponding_Record_Type (BT2);
952 -- Ada 2005 (AI-251): A class-wide abstract interface type T1
953 -- covers an object T2 that implements a direct derivation of T1.
954 -- Note: test for presence of E is defense against previous error.
958 -- If expansion is disabled the Corresponding_Record_Type may
959 -- not be available yet, so use the interface list in the
960 -- declaration directly.
963 and then Nkind (Parent (BT2)) = N_Protected_Type_Declaration
964 and then Present (Interface_List (Parent (BT2)))
967 Intf : Node_Id := First (Interface_List (Parent (BT2)));
969 while Present (Intf) loop
970 if Is_Ancestor (Etype (T1), Entity (Intf)) then
981 Check_Error_Detected;
984 -- Here we have a corresponding record type
986 elsif Present (Interfaces (E)) then
987 Elmt := First_Elmt (Interfaces (E));
988 while Present (Elmt) loop
989 if Is_Ancestor (Etype (T1), Node (Elmt)) then
997 -- We should also check the case in which T1 is an ancestor of
998 -- some implemented interface???
1003 -- In a dispatching call, the formal is of some specific type, and the
1004 -- actual is of the corresponding class-wide type, including a subtype
1005 -- of the class-wide type.
1007 elsif Is_Class_Wide_Type (T2)
1009 (Class_Wide_Type (T1) = Class_Wide_Type (T2)
1010 or else Base_Type (Root_Type (T2)) = BT1)
1014 -- Some contexts require a class of types rather than a specific type.
1015 -- For example, conditions require any boolean type, fixed point
1016 -- attributes require some real type, etc. The built-in types Any_XXX
1017 -- represent these classes.
1019 elsif (T1 = Any_Integer and then Is_Integer_Type (T2))
1020 or else (T1 = Any_Boolean and then Is_Boolean_Type (T2))
1021 or else (T1 = Any_Real and then Is_Real_Type (T2))
1022 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
1023 or else (T1 = Any_Discrete and then Is_Discrete_Type (T2))
1027 -- An aggregate is compatible with an array or record type
1029 elsif T2 = Any_Composite and then Is_Aggregate_Type (T1) then
1032 -- If the expected type is an anonymous access, the designated type must
1033 -- cover that of the expression. Use the base type for this check: even
1034 -- though access subtypes are rare in sources, they are generated for
1035 -- actuals in instantiations.
1037 elsif Ekind (BT1) = E_Anonymous_Access_Type
1038 and then Is_Access_Type (T2)
1039 and then Covers (Designated_Type (T1), Designated_Type (T2))
1043 -- Ada 2012 (AI05-0149): Allow an anonymous access type in the context
1044 -- of a named general access type. An implicit conversion will be
1045 -- applied. For the resolution, one designated type must cover the
1048 elsif Ada_Version >= Ada_2012
1049 and then Ekind (BT1) = E_General_Access_Type
1050 and then Ekind (BT2) = E_Anonymous_Access_Type
1051 and then (Covers (Designated_Type (T1), Designated_Type (T2))
1053 Covers (Designated_Type (T2), Designated_Type (T1)))
1057 -- An Access_To_Subprogram is compatible with itself, or with an
1058 -- anonymous type created for an attribute reference Access.
1060 elsif Ekind_In (BT1, E_Access_Subprogram_Type,
1061 E_Access_Protected_Subprogram_Type)
1062 and then Is_Access_Type (T2)
1063 and then (not Comes_From_Source (T1)
1064 or else not Comes_From_Source (T2))
1065 and then (Is_Overloadable (Designated_Type (T2))
1066 or else Ekind (Designated_Type (T2)) = E_Subprogram_Type)
1067 and then Type_Conformant (Designated_Type (T1), Designated_Type (T2))
1068 and then Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
1072 -- Ada 2005 (AI-254): An Anonymous_Access_To_Subprogram is compatible
1073 -- with itself, or with an anonymous type created for an attribute
1074 -- reference Access.
1076 elsif Ekind_In (BT1, E_Anonymous_Access_Subprogram_Type,
1077 E_Anonymous_Access_Protected_Subprogram_Type)
1078 and then Is_Access_Type (T2)
1079 and then (not Comes_From_Source (T1)
1080 or else not Comes_From_Source (T2))
1081 and then (Is_Overloadable (Designated_Type (T2))
1082 or else Ekind (Designated_Type (T2)) = E_Subprogram_Type)
1083 and then Type_Conformant (Designated_Type (T1), Designated_Type (T2))
1084 and then Mode_Conformant (Designated_Type (T1), Designated_Type (T2))
1088 -- The context can be a remote access type, and the expression the
1089 -- corresponding source type declared in a categorized package, or
1092 elsif Is_Record_Type (T1)
1093 and then (Is_Remote_Call_Interface (T1) or else Is_Remote_Types (T1))
1094 and then Present (Corresponding_Remote_Type (T1))
1096 return Covers (Corresponding_Remote_Type (T1), T2);
1100 elsif Is_Record_Type (T2)
1101 and then (Is_Remote_Call_Interface (T2) or else Is_Remote_Types (T2))
1102 and then Present (Corresponding_Remote_Type (T2))
1104 return Covers (Corresponding_Remote_Type (T2), T1);
1106 -- Synchronized types are represented at run time by their corresponding
1107 -- record type. During expansion one is replaced with the other, but
1108 -- they are compatible views of the same type.
1110 elsif Is_Record_Type (T1)
1111 and then Is_Concurrent_Type (T2)
1112 and then Present (Corresponding_Record_Type (T2))
1114 return Covers (T1, Corresponding_Record_Type (T2));
1116 elsif Is_Concurrent_Type (T1)
1117 and then Present (Corresponding_Record_Type (T1))
1118 and then Is_Record_Type (T2)
1120 return Covers (Corresponding_Record_Type (T1), T2);
1122 -- During analysis, an attribute reference 'Access has a special type
1123 -- kind: Access_Attribute_Type, to be replaced eventually with the type
1124 -- imposed by context.
1126 elsif Ekind (T2) = E_Access_Attribute_Type
1127 and then Ekind_In (BT1, E_General_Access_Type, E_Access_Type)
1128 and then Covers (Designated_Type (T1), Designated_Type (T2))
1130 -- If the target type is a RACW type while the source is an access
1131 -- attribute type, we are building a RACW that may be exported.
1133 if Is_Remote_Access_To_Class_Wide_Type (BT1) then
1134 Set_Has_RACW (Current_Sem_Unit);
1139 -- Ditto for allocators, which eventually resolve to the context type
1141 elsif Ekind (T2) = E_Allocator_Type and then Is_Access_Type (T1) then
1142 return Covers (Designated_Type (T1), Designated_Type (T2))
1144 (From_Limited_With (Designated_Type (T1))
1145 and then Covers (Designated_Type (T2), Designated_Type (T1)));
1147 -- A boolean operation on integer literals is compatible with modular
1150 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
1153 -- The actual type may be the result of a previous error
1155 elsif BT2 = Any_Type then
1158 -- A Raise_Expressions is legal in any expression context
1160 elsif BT2 = Raise_Type then
1163 -- A packed array type covers its corresponding non-packed type. This is
1164 -- not legitimate Ada, but allows the omission of a number of otherwise
1165 -- useless unchecked conversions, and since this can only arise in
1166 -- (known correct) expanded code, no harm is done.
1168 elsif Is_Array_Type (T2)
1169 and then Is_Packed (T2)
1170 and then T1 = Packed_Array_Impl_Type (T2)
1174 -- Similarly an array type covers its corresponding packed array type
1176 elsif Is_Array_Type (T1)
1177 and then Is_Packed (T1)
1178 and then T2 = Packed_Array_Impl_Type (T1)
1182 -- In instances, or with types exported from instantiations, check
1183 -- whether a partial and a full view match. Verify that types are
1184 -- legal, to prevent cascaded errors.
1187 and then (Full_View_Covers (T1, T2) or else Full_View_Covers (T2, T1))
1192 and then Is_Generic_Actual_Type (T2)
1193 and then Full_View_Covers (T1, T2)
1198 and then Is_Generic_Actual_Type (T1)
1199 and then Full_View_Covers (T2, T1)
1203 -- In the expansion of inlined bodies, types are compatible if they
1204 -- are structurally equivalent.
1206 elsif In_Inlined_Body
1207 and then (Underlying_Type (T1) = Underlying_Type (T2)
1209 (Is_Access_Type (T1)
1210 and then Is_Access_Type (T2)
1211 and then Designated_Type (T1) = Designated_Type (T2))
1214 and then Is_Access_Type (Underlying_Type (T2)))
1217 and then Is_Composite_Type (Underlying_Type (T1))))
1221 -- Ada 2005 (AI-50217): Additional branches to make the shadow entity
1222 -- obtained through a limited_with compatible with its real entity.
1224 elsif From_Limited_With (T1) then
1226 -- If the expected type is the non-limited view of a type, the
1227 -- expression may have the limited view. If that one in turn is
1228 -- incomplete, get full view if available.
1230 return Has_Non_Limited_View (T1)
1231 and then Covers (Get_Full_View (Non_Limited_View (T1)), T2);
1233 elsif From_Limited_With (T2) then
1235 -- If units in the context have Limited_With clauses on each other,
1236 -- either type might have a limited view. Checks performed elsewhere
1237 -- verify that the context type is the nonlimited view.
1239 return Has_Non_Limited_View (T2)
1240 and then Covers (T1, Get_Full_View (Non_Limited_View (T2)));
1242 -- Ada 2005 (AI-412): Coverage for regular incomplete subtypes
1244 elsif Ekind (T1) = E_Incomplete_Subtype then
1245 return Covers (Full_View (Etype (T1)), T2);
1247 elsif Ekind (T2) = E_Incomplete_Subtype then
1248 return Covers (T1, Full_View (Etype (T2)));
1250 -- Ada 2005 (AI-423): Coverage of formal anonymous access types
1251 -- and actual anonymous access types in the context of generic
1252 -- instantiations. We have the following situation:
1255 -- type Formal is private;
1256 -- Formal_Obj : access Formal; -- T1
1260 -- type Actual is ...
1261 -- Actual_Obj : access Actual; -- T2
1262 -- package Instance is new G (Formal => Actual,
1263 -- Formal_Obj => Actual_Obj);
1265 elsif Ada_Version >= Ada_2005
1266 and then Ekind (T1) = E_Anonymous_Access_Type
1267 and then Ekind (T2) = E_Anonymous_Access_Type
1268 and then Is_Generic_Type (Directly_Designated_Type (T1))
1269 and then Get_Instance_Of (Directly_Designated_Type (T1)) =
1270 Directly_Designated_Type (T2)
1274 -- Otherwise, types are not compatible
1285 function Disambiguate
1287 I1, I2 : Interp_Index;
1288 Typ : Entity_Id) return Interp
1293 Nam1, Nam2 : Entity_Id;
1294 Predef_Subp : Entity_Id;
1295 User_Subp : Entity_Id;
1297 function Inherited_From_Actual (S : Entity_Id) return Boolean;
1298 -- Determine whether one of the candidates is an operation inherited by
1299 -- a type that is derived from an actual in an instantiation.
1301 function In_Same_Declaration_List
1303 Op_Decl : Entity_Id) return Boolean;
1304 -- AI05-0020: a spurious ambiguity may arise when equality on anonymous
1305 -- access types is declared on the partial view of a designated type, so
1306 -- that the type declaration and equality are not in the same list of
1307 -- declarations. This AI gives a preference rule for the user-defined
1308 -- operation. Same rule applies for arithmetic operations on private
1309 -- types completed with fixed-point types: the predefined operation is
1310 -- hidden; this is already handled properly in GNAT.
1312 function Is_Actual_Subprogram (S : Entity_Id) return Boolean;
1313 -- Determine whether a subprogram is an actual in an enclosing instance.
1314 -- An overloading between such a subprogram and one declared outside the
1315 -- instance is resolved in favor of the first, because it resolved in
1316 -- the generic. Within the instance the actual is represented by a
1317 -- constructed subprogram renaming.
1319 function Matches (Actual, Formal : Node_Id) return Boolean;
1320 -- Look for exact type match in an instance, to remove spurious
1321 -- ambiguities when two formal types have the same actual.
1323 function Operand_Type return Entity_Id;
1324 -- Determine type of operand for an equality operation, to apply
1325 -- Ada 2005 rules to equality on anonymous access types.
1327 function Standard_Operator return Boolean;
1328 -- Check whether subprogram is predefined operator declared in Standard.
1329 -- It may given by an operator name, or by an expanded name whose prefix
1332 function Remove_Conversions return Interp;
1333 -- Last chance for pathological cases involving comparisons on literals,
1334 -- and user overloadings of the same operator. Such pathologies have
1335 -- been removed from the ACVC, but still appear in two DEC tests, with
1336 -- the following notable quote from Ben Brosgol:
1338 -- [Note: I disclaim all credit/responsibility/blame for coming up with
1339 -- this example; Robert Dewar brought it to our attention, since it is
1340 -- apparently found in the ACVC 1.5. I did not attempt to find the
1341 -- reason in the Reference Manual that makes the example legal, since I
1342 -- was too nauseated by it to want to pursue it further.]
1344 -- Accordingly, this is not a fully recursive solution, but it handles
1345 -- DEC tests c460vsa, c460vsb. It also handles ai00136a, which pushes
1346 -- pathology in the other direction with calls whose multiple overloaded
1347 -- actuals make them truly unresolvable.
1349 -- The new rules concerning abstract operations create additional need
1350 -- for special handling of expressions with universal operands, see
1351 -- comments to Has_Abstract_Interpretation below.
1353 ---------------------------
1354 -- Inherited_From_Actual --
1355 ---------------------------
1357 function Inherited_From_Actual (S : Entity_Id) return Boolean is
1358 Par : constant Node_Id := Parent (S);
1360 if Nkind (Par) /= N_Full_Type_Declaration
1361 or else Nkind (Type_Definition (Par)) /= N_Derived_Type_Definition
1365 return Is_Entity_Name (Subtype_Indication (Type_Definition (Par)))
1367 Is_Generic_Actual_Type (
1368 Entity (Subtype_Indication (Type_Definition (Par))));
1370 end Inherited_From_Actual;
1372 ------------------------------
1373 -- In_Same_Declaration_List --
1374 ------------------------------
1376 function In_Same_Declaration_List
1378 Op_Decl : Entity_Id) return Boolean
1380 Scop : constant Entity_Id := Scope (Typ);
1383 return In_Same_List (Parent (Typ), Op_Decl)
1385 (Ekind_In (Scop, E_Package, E_Generic_Package)
1386 and then List_Containing (Op_Decl) =
1387 Visible_Declarations (Parent (Scop))
1388 and then List_Containing (Parent (Typ)) =
1389 Private_Declarations (Parent (Scop)));
1390 end In_Same_Declaration_List;
1392 --------------------------
1393 -- Is_Actual_Subprogram --
1394 --------------------------
1396 function Is_Actual_Subprogram (S : Entity_Id) return Boolean is
1398 return In_Open_Scopes (Scope (S))
1399 and then Nkind (Unit_Declaration_Node (S)) =
1400 N_Subprogram_Renaming_Declaration
1402 -- Why the Comes_From_Source test here???
1404 and then not Comes_From_Source (Unit_Declaration_Node (S))
1407 (Is_Generic_Instance (Scope (S))
1408 or else Is_Wrapper_Package (Scope (S)));
1409 end Is_Actual_Subprogram;
1415 function Matches (Actual, Formal : Node_Id) return Boolean is
1416 T1 : constant Entity_Id := Etype (Actual);
1417 T2 : constant Entity_Id := Etype (Formal);
1421 (Is_Numeric_Type (T2)
1422 and then (T1 = Universal_Real or else T1 = Universal_Integer));
1429 function Operand_Type return Entity_Id is
1433 if Nkind (N) = N_Function_Call then
1434 Opnd := First_Actual (N);
1436 Opnd := Left_Opnd (N);
1439 return Etype (Opnd);
1442 ------------------------
1443 -- Remove_Conversions --
1444 ------------------------
1446 function Remove_Conversions return Interp is
1454 function Has_Abstract_Interpretation (N : Node_Id) return Boolean;
1455 -- If an operation has universal operands the universal operation
1456 -- is present among its interpretations. If there is an abstract
1457 -- interpretation for the operator, with a numeric result, this
1458 -- interpretation was already removed in sem_ch4, but the universal
1459 -- one is still visible. We must rescan the list of operators and
1460 -- remove the universal interpretation to resolve the ambiguity.
1462 ---------------------------------
1463 -- Has_Abstract_Interpretation --
1464 ---------------------------------
1466 function Has_Abstract_Interpretation (N : Node_Id) return Boolean is
1470 if Nkind (N) not in N_Op
1471 or else Ada_Version < Ada_2005
1472 or else not Is_Overloaded (N)
1473 or else No (Universal_Interpretation (N))
1478 E := Get_Name_Entity_Id (Chars (N));
1479 while Present (E) loop
1480 if Is_Overloadable (E)
1481 and then Is_Abstract_Subprogram (E)
1482 and then Is_Numeric_Type (Etype (E))
1490 -- Finally, if an operand of the binary operator is itself
1491 -- an operator, recurse to see whether its own abstract
1492 -- interpretation is responsible for the spurious ambiguity.
1494 if Nkind (N) in N_Binary_Op then
1495 return Has_Abstract_Interpretation (Left_Opnd (N))
1496 or else Has_Abstract_Interpretation (Right_Opnd (N));
1498 elsif Nkind (N) in N_Unary_Op then
1499 return Has_Abstract_Interpretation (Right_Opnd (N));
1505 end Has_Abstract_Interpretation;
1507 -- Start of processing for Remove_Conversions
1512 Get_First_Interp (N, I, It);
1513 while Present (It.Typ) loop
1514 if not Is_Overloadable (It.Nam) then
1518 F1 := First_Formal (It.Nam);
1524 if Nkind (N) in N_Subprogram_Call then
1525 Act1 := First_Actual (N);
1527 if Present (Act1) then
1528 Act2 := Next_Actual (Act1);
1533 elsif Nkind (N) in N_Unary_Op then
1534 Act1 := Right_Opnd (N);
1537 elsif Nkind (N) in N_Binary_Op then
1538 Act1 := Left_Opnd (N);
1539 Act2 := Right_Opnd (N);
1541 -- Use type of second formal, so as to include
1542 -- exponentiation, where the exponent may be
1543 -- ambiguous and the result non-universal.
1551 if Nkind (Act1) in N_Op
1552 and then Is_Overloaded (Act1)
1553 and then Nkind_In (Left_Opnd (Act1), N_Integer_Literal,
1555 and then Nkind_In (Right_Opnd (Act1), N_Integer_Literal,
1557 and then Has_Compatible_Type (Act1, Standard_Boolean)
1558 and then Etype (F1) = Standard_Boolean
1560 -- If the two candidates are the original ones, the
1561 -- ambiguity is real. Otherwise keep the original, further
1562 -- calls to Disambiguate will take care of others in the
1563 -- list of candidates.
1565 if It1 /= No_Interp then
1566 if It = Disambiguate.It1
1567 or else It = Disambiguate.It2
1569 if It1 = Disambiguate.It1
1570 or else It1 = Disambiguate.It2
1578 elsif Present (Act2)
1579 and then Nkind (Act2) in N_Op
1580 and then Is_Overloaded (Act2)
1581 and then Nkind_In (Right_Opnd (Act2), N_Integer_Literal,
1583 and then Has_Compatible_Type (Act2, Standard_Boolean)
1585 -- The preference rule on the first actual is not
1586 -- sufficient to disambiguate.
1594 elsif Is_Numeric_Type (Etype (F1))
1595 and then Has_Abstract_Interpretation (Act1)
1597 -- Current interpretation is not the right one because it
1598 -- expects a numeric operand. Examine all the other ones.
1605 Get_First_Interp (N, I, It);
1606 while Present (It.Typ) loop
1608 not Is_Numeric_Type (Etype (First_Formal (It.Nam)))
1611 or else not Has_Abstract_Interpretation (Act2)
1614 (Etype (Next_Formal (First_Formal (It.Nam))))
1620 Get_Next_Interp (I, It);
1629 Get_Next_Interp (I, It);
1632 -- After some error, a formal may have Any_Type and yield a spurious
1633 -- match. To avoid cascaded errors if possible, check for such a
1634 -- formal in either candidate.
1636 if Serious_Errors_Detected > 0 then
1641 Formal := First_Formal (Nam1);
1642 while Present (Formal) loop
1643 if Etype (Formal) = Any_Type then
1644 return Disambiguate.It2;
1647 Next_Formal (Formal);
1650 Formal := First_Formal (Nam2);
1651 while Present (Formal) loop
1652 if Etype (Formal) = Any_Type then
1653 return Disambiguate.It1;
1656 Next_Formal (Formal);
1662 end Remove_Conversions;
1664 -----------------------
1665 -- Standard_Operator --
1666 -----------------------
1668 function Standard_Operator return Boolean is
1672 if Nkind (N) in N_Op then
1675 elsif Nkind (N) = N_Function_Call then
1678 if Nkind (Nam) /= N_Expanded_Name then
1681 return Entity (Prefix (Nam)) = Standard_Standard;
1686 end Standard_Operator;
1688 -- Start of processing for Disambiguate
1691 -- Recover the two legal interpretations
1693 Get_First_Interp (N, I, It);
1695 Get_Next_Interp (I, It);
1701 Get_Next_Interp (I, It);
1707 -- Check whether one of the entities is an Ada 2005/2012 and we are
1708 -- operating in an earlier mode, in which case we discard the Ada
1709 -- 2005/2012 entity, so that we get proper Ada 95 overload resolution.
1711 if Ada_Version < Ada_2005 then
1712 if Is_Ada_2005_Only (Nam1) or else Is_Ada_2012_Only (Nam1) then
1714 elsif Is_Ada_2005_Only (Nam2) or else Is_Ada_2012_Only (Nam1) then
1719 -- Check whether one of the entities is an Ada 2012 entity and we are
1720 -- operating in Ada 2005 mode, in which case we discard the Ada 2012
1721 -- entity, so that we get proper Ada 2005 overload resolution.
1723 if Ada_Version = Ada_2005 then
1724 if Is_Ada_2012_Only (Nam1) then
1726 elsif Is_Ada_2012_Only (Nam2) then
1731 -- Check for overloaded CIL convention stuff because the CIL libraries
1732 -- do sick things like Console.Write_Line where it matches two different
1733 -- overloads, so just pick the first ???
1735 if Convention (Nam1) = Convention_CIL
1736 and then Convention (Nam2) = Convention_CIL
1737 and then Ekind (Nam1) = Ekind (Nam2)
1738 and then Ekind_In (Nam1, E_Procedure, E_Function)
1743 -- If the context is universal, the predefined operator is preferred.
1744 -- This includes bounds in numeric type declarations, and expressions
1745 -- in type conversions. If no interpretation yields a universal type,
1746 -- then we must check whether the user-defined entity hides the prede-
1749 if Chars (Nam1) in Any_Operator_Name and then Standard_Operator then
1750 if Typ = Universal_Integer
1751 or else Typ = Universal_Real
1752 or else Typ = Any_Integer
1753 or else Typ = Any_Discrete
1754 or else Typ = Any_Real
1755 or else Typ = Any_Type
1757 -- Find an interpretation that yields the universal type, or else
1758 -- a predefined operator that yields a predefined numeric type.
1761 Candidate : Interp := No_Interp;
1764 Get_First_Interp (N, I, It);
1765 while Present (It.Typ) loop
1766 if (Covers (Typ, It.Typ) or else Typ = Any_Type)
1768 (It.Typ = Universal_Integer
1769 or else It.Typ = Universal_Real)
1773 elsif Covers (Typ, It.Typ)
1774 and then Scope (It.Typ) = Standard_Standard
1775 and then Scope (It.Nam) = Standard_Standard
1776 and then Is_Numeric_Type (It.Typ)
1781 Get_Next_Interp (I, It);
1784 if Candidate /= No_Interp then
1789 elsif Chars (Nam1) /= Name_Op_Not
1790 and then (Typ = Standard_Boolean or else Typ = Any_Boolean)
1792 -- Equality or comparison operation. Choose predefined operator if
1793 -- arguments are universal. The node may be an operator, name, or
1794 -- a function call, so unpack arguments accordingly.
1797 Arg1, Arg2 : Node_Id;
1800 if Nkind (N) in N_Op then
1801 Arg1 := Left_Opnd (N);
1802 Arg2 := Right_Opnd (N);
1804 elsif Is_Entity_Name (N) then
1805 Arg1 := First_Entity (Entity (N));
1806 Arg2 := Next_Entity (Arg1);
1809 Arg1 := First_Actual (N);
1810 Arg2 := Next_Actual (Arg1);
1814 and then Present (Universal_Interpretation (Arg1))
1815 and then Universal_Interpretation (Arg2) =
1816 Universal_Interpretation (Arg1)
1818 Get_First_Interp (N, I, It);
1819 while Scope (It.Nam) /= Standard_Standard loop
1820 Get_Next_Interp (I, It);
1829 -- If no universal interpretation, check whether user-defined operator
1830 -- hides predefined one, as well as other special cases. If the node
1831 -- is a range, then one or both bounds are ambiguous. Each will have
1832 -- to be disambiguated w.r.t. the context type. The type of the range
1833 -- itself is imposed by the context, so we can return either legal
1836 if Ekind (Nam1) = E_Operator then
1837 Predef_Subp := Nam1;
1840 elsif Ekind (Nam2) = E_Operator then
1841 Predef_Subp := Nam2;
1844 elsif Nkind (N) = N_Range then
1847 -- Implement AI05-105: A renaming declaration with an access
1848 -- definition must resolve to an anonymous access type. This
1849 -- is a resolution rule and can be used to disambiguate.
1851 elsif Nkind (Parent (N)) = N_Object_Renaming_Declaration
1852 and then Present (Access_Definition (Parent (N)))
1854 if Ekind_In (It1.Typ, E_Anonymous_Access_Type,
1855 E_Anonymous_Access_Subprogram_Type)
1857 if Ekind (It2.Typ) = Ekind (It1.Typ) then
1867 elsif Ekind_In (It2.Typ, E_Anonymous_Access_Type,
1868 E_Anonymous_Access_Subprogram_Type)
1872 -- No legal interpretation
1878 -- If two user defined-subprograms are visible, it is a true ambiguity,
1879 -- unless one of them is an entry and the context is a conditional or
1880 -- timed entry call, or unless we are within an instance and this is
1881 -- results from two formals types with the same actual.
1884 if Nkind (N) = N_Procedure_Call_Statement
1885 and then Nkind (Parent (N)) = N_Entry_Call_Alternative
1886 and then N = Entry_Call_Statement (Parent (N))
1888 if Ekind (Nam2) = E_Entry then
1890 elsif Ekind (Nam1) = E_Entry then
1896 -- If the ambiguity occurs within an instance, it is due to several
1897 -- formal types with the same actual. Look for an exact match between
1898 -- the types of the formals of the overloadable entities, and the
1899 -- actuals in the call, to recover the unambiguous match in the
1900 -- original generic.
1902 -- The ambiguity can also be due to an overloading between a formal
1903 -- subprogram and a subprogram declared outside the generic. If the
1904 -- node is overloaded, it did not resolve to the global entity in
1905 -- the generic, and we choose the formal subprogram.
1907 -- Finally, the ambiguity can be between an explicit subprogram and
1908 -- one inherited (with different defaults) from an actual. In this
1909 -- case the resolution was to the explicit declaration in the
1910 -- generic, and remains so in the instance.
1912 -- The same sort of disambiguation needed for calls is also required
1913 -- for the name given in a subprogram renaming, and that case is
1914 -- handled here as well. We test Comes_From_Source to exclude this
1915 -- treatment for implicit renamings created for formal subprograms.
1917 elsif In_Instance and then not In_Generic_Actual (N) then
1918 if Nkind (N) in N_Subprogram_Call
1920 (Nkind (N) in N_Has_Entity
1922 Nkind (Parent (N)) = N_Subprogram_Renaming_Declaration
1923 and then Comes_From_Source (Parent (N)))
1928 Renam : Entity_Id := Empty;
1929 Is_Act1 : constant Boolean := Is_Actual_Subprogram (Nam1);
1930 Is_Act2 : constant Boolean := Is_Actual_Subprogram (Nam2);
1933 if Is_Act1 and then not Is_Act2 then
1936 elsif Is_Act2 and then not Is_Act1 then
1939 elsif Inherited_From_Actual (Nam1)
1940 and then Comes_From_Source (Nam2)
1944 elsif Inherited_From_Actual (Nam2)
1945 and then Comes_From_Source (Nam1)
1950 -- In the case of a renamed subprogram, pick up the entity
1951 -- of the renaming declaration so we can traverse its
1952 -- formal parameters.
1954 if Nkind (N) in N_Has_Entity then
1955 Renam := Defining_Unit_Name (Specification (Parent (N)));
1958 if Present (Renam) then
1959 Actual := First_Formal (Renam);
1961 Actual := First_Actual (N);
1964 Formal := First_Formal (Nam1);
1965 while Present (Actual) loop
1966 if Etype (Actual) /= Etype (Formal) then
1970 if Present (Renam) then
1971 Next_Formal (Actual);
1973 Next_Actual (Actual);
1976 Next_Formal (Formal);
1982 elsif Nkind (N) in N_Binary_Op then
1983 if Matches (Left_Opnd (N), First_Formal (Nam1))
1985 Matches (Right_Opnd (N), Next_Formal (First_Formal (Nam1)))
1992 elsif Nkind (N) in N_Unary_Op then
1993 if Etype (Right_Opnd (N)) = Etype (First_Formal (Nam1)) then
2000 return Remove_Conversions;
2003 return Remove_Conversions;
2007 -- An implicit concatenation operator on a string type cannot be
2008 -- disambiguated from the predefined concatenation. This can only
2009 -- happen with concatenation of string literals.
2011 if Chars (User_Subp) = Name_Op_Concat
2012 and then Ekind (User_Subp) = E_Operator
2013 and then Is_String_Type (Etype (First_Formal (User_Subp)))
2017 -- If the user-defined operator is in an open scope, or in the scope
2018 -- of the resulting type, or given by an expanded name that names its
2019 -- scope, it hides the predefined operator for the type. Exponentiation
2020 -- has to be special-cased because the implicit operator does not have
2021 -- a symmetric signature, and may not be hidden by the explicit one.
2023 elsif (Nkind (N) = N_Function_Call
2024 and then Nkind (Name (N)) = N_Expanded_Name
2025 and then (Chars (Predef_Subp) /= Name_Op_Expon
2026 or else Hides_Op (User_Subp, Predef_Subp))
2027 and then Scope (User_Subp) = Entity (Prefix (Name (N))))
2028 or else Hides_Op (User_Subp, Predef_Subp)
2030 if It1.Nam = User_Subp then
2036 -- Otherwise, the predefined operator has precedence, or if the user-
2037 -- defined operation is directly visible we have a true ambiguity.
2039 -- If this is a fixed-point multiplication and division in Ada 83 mode,
2040 -- exclude the universal_fixed operator, which often causes ambiguities
2043 -- Ditto in Ada 2012, where an ambiguity may arise for an operation
2044 -- on a partial view that is completed with a fixed point type. See
2045 -- AI05-0020 and AI05-0209. The ambiguity is resolved in favor of the
2046 -- user-defined type and subprogram, so that a client of the package
2047 -- has the same resolution as the body of the package.
2050 if (In_Open_Scopes (Scope (User_Subp))
2051 or else Is_Potentially_Use_Visible (User_Subp))
2052 and then not In_Instance
2054 if Is_Fixed_Point_Type (Typ)
2055 and then Nam_In (Chars (Nam1), Name_Op_Multiply, Name_Op_Divide)
2057 (Ada_Version = Ada_83
2058 or else (Ada_Version >= Ada_2012
2059 and then In_Same_Declaration_List
2060 (First_Subtype (Typ),
2061 Unit_Declaration_Node (User_Subp))))
2063 if It2.Nam = Predef_Subp then
2069 -- Ada 2005, AI-420: preference rule for "=" on Universal_Access
2070 -- states that the operator defined in Standard is not available
2071 -- if there is a user-defined equality with the proper signature,
2072 -- declared in the same declarative list as the type. The node
2073 -- may be an operator or a function call.
2075 elsif Nam_In (Chars (Nam1), Name_Op_Eq, Name_Op_Ne)
2076 and then Ada_Version >= Ada_2005
2077 and then Etype (User_Subp) = Standard_Boolean
2078 and then Ekind (Operand_Type) = E_Anonymous_Access_Type
2080 In_Same_Declaration_List
2081 (Designated_Type (Operand_Type),
2082 Unit_Declaration_Node (User_Subp))
2084 if It2.Nam = Predef_Subp then
2090 -- An immediately visible operator hides a use-visible user-
2091 -- defined operation. This disambiguation cannot take place
2092 -- earlier because the visibility of the predefined operator
2093 -- can only be established when operand types are known.
2095 elsif Ekind (User_Subp) = E_Function
2096 and then Ekind (Predef_Subp) = E_Operator
2097 and then Nkind (N) in N_Op
2098 and then not Is_Overloaded (Right_Opnd (N))
2100 Is_Immediately_Visible (Base_Type (Etype (Right_Opnd (N))))
2101 and then Is_Potentially_Use_Visible (User_Subp)
2103 if It2.Nam = Predef_Subp then
2113 elsif It1.Nam = Predef_Subp then
2122 ---------------------
2123 -- End_Interp_List --
2124 ---------------------
2126 procedure End_Interp_List is
2128 All_Interp.Table (All_Interp.Last) := No_Interp;
2129 All_Interp.Increment_Last;
2130 end End_Interp_List;
2132 -------------------------
2133 -- Entity_Matches_Spec --
2134 -------------------------
2136 function Entity_Matches_Spec (Old_S, New_S : Entity_Id) return Boolean is
2138 -- Simple case: same entity kinds, type conformance is required. A
2139 -- parameterless function can also rename a literal.
2141 if Ekind (Old_S) = Ekind (New_S)
2142 or else (Ekind (New_S) = E_Function
2143 and then Ekind (Old_S) = E_Enumeration_Literal)
2145 return Type_Conformant (New_S, Old_S);
2147 elsif Ekind (New_S) = E_Function and then Ekind (Old_S) = E_Operator then
2148 return Operator_Matches_Spec (Old_S, New_S);
2150 elsif Ekind (New_S) = E_Procedure and then Is_Entry (Old_S) then
2151 return Type_Conformant (New_S, Old_S);
2156 end Entity_Matches_Spec;
2158 ----------------------
2159 -- Find_Unique_Type --
2160 ----------------------
2162 function Find_Unique_Type (L : Node_Id; R : Node_Id) return Entity_Id is
2163 T : constant Entity_Id := Etype (L);
2166 TR : Entity_Id := Any_Type;
2169 if Is_Overloaded (R) then
2170 Get_First_Interp (R, I, It);
2171 while Present (It.Typ) loop
2172 if Covers (T, It.Typ) or else Covers (It.Typ, T) then
2174 -- If several interpretations are possible and L is universal,
2175 -- apply preference rule.
2177 if TR /= Any_Type then
2178 if (T = Universal_Integer or else T = Universal_Real)
2189 Get_Next_Interp (I, It);
2194 -- In the non-overloaded case, the Etype of R is already set correctly
2200 -- If one of the operands is Universal_Fixed, the type of the other
2201 -- operand provides the context.
2203 if Etype (R) = Universal_Fixed then
2206 elsif T = Universal_Fixed then
2209 -- Ada 2005 (AI-230): Support the following operators:
2211 -- function "=" (L, R : universal_access) return Boolean;
2212 -- function "/=" (L, R : universal_access) return Boolean;
2214 -- Pool specific access types (E_Access_Type) are not covered by these
2215 -- operators because of the legality rule of 4.5.2(9.2): "The operands
2216 -- of the equality operators for universal_access shall be convertible
2217 -- to one another (see 4.6)". For example, considering the type decla-
2218 -- ration "type P is access Integer" and an anonymous access to Integer,
2219 -- P is convertible to "access Integer" by 4.6 (24.11-24.15), but there
2220 -- is no rule in 4.6 that allows "access Integer" to be converted to P.
2222 elsif Ada_Version >= Ada_2005
2223 and then Ekind_In (Etype (L), E_Anonymous_Access_Type,
2224 E_Anonymous_Access_Subprogram_Type)
2225 and then Is_Access_Type (Etype (R))
2226 and then Ekind (Etype (R)) /= E_Access_Type
2230 elsif Ada_Version >= Ada_2005
2231 and then Ekind_In (Etype (R), E_Anonymous_Access_Type,
2232 E_Anonymous_Access_Subprogram_Type)
2233 and then Is_Access_Type (Etype (L))
2234 and then Ekind (Etype (L)) /= E_Access_Type
2238 -- If one operand is a raise_expression, use type of other operand
2240 elsif Nkind (L) = N_Raise_Expression then
2244 return Specific_Type (T, Etype (R));
2246 end Find_Unique_Type;
2248 -------------------------------------
2249 -- Function_Interp_Has_Abstract_Op --
2250 -------------------------------------
2252 function Function_Interp_Has_Abstract_Op
2254 E : Entity_Id) return Entity_Id
2256 Abstr_Op : Entity_Id;
2259 Form_Parm : Node_Id;
2262 -- Why is check on E needed below ???
2263 -- In any case this para needs comments ???
2265 if Is_Overloaded (N) and then Is_Overloadable (E) then
2266 Act_Parm := First_Actual (N);
2267 Form_Parm := First_Formal (E);
2268 while Present (Act_Parm) and then Present (Form_Parm) loop
2271 if Nkind (Act) = N_Parameter_Association then
2272 Act := Explicit_Actual_Parameter (Act);
2275 Abstr_Op := Has_Abstract_Op (Act, Etype (Form_Parm));
2277 if Present (Abstr_Op) then
2281 Next_Actual (Act_Parm);
2282 Next_Formal (Form_Parm);
2287 end Function_Interp_Has_Abstract_Op;
2289 ----------------------
2290 -- Get_First_Interp --
2291 ----------------------
2293 procedure Get_First_Interp
2295 I : out Interp_Index;
2298 Int_Ind : Interp_Index;
2303 -- If a selected component is overloaded because the selector has
2304 -- multiple interpretations, the node is a call to a protected
2305 -- operation or an indirect call. Retrieve the interpretation from
2306 -- the selector name. The selected component may be overloaded as well
2307 -- if the prefix is overloaded. That case is unchanged.
2309 if Nkind (N) = N_Selected_Component
2310 and then Is_Overloaded (Selector_Name (N))
2312 O_N := Selector_Name (N);
2317 Map_Ptr := Headers (Hash (O_N));
2318 while Map_Ptr /= No_Entry loop
2319 if Interp_Map.Table (Map_Ptr).Node = O_N then
2320 Int_Ind := Interp_Map.Table (Map_Ptr).Index;
2321 It := All_Interp.Table (Int_Ind);
2325 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
2329 -- Procedure should never be called if the node has no interpretations
2331 raise Program_Error;
2332 end Get_First_Interp;
2334 ---------------------
2335 -- Get_Next_Interp --
2336 ---------------------
2338 procedure Get_Next_Interp (I : in out Interp_Index; It : out Interp) is
2341 It := All_Interp.Table (I);
2342 end Get_Next_Interp;
2344 -------------------------
2345 -- Has_Compatible_Type --
2346 -------------------------
2348 function Has_Compatible_Type
2350 Typ : Entity_Id) return Boolean
2360 if Nkind (N) = N_Subtype_Indication
2361 or else not Is_Overloaded (N)
2364 Covers (Typ, Etype (N))
2366 -- Ada 2005 (AI-345): The context may be a synchronized interface.
2367 -- If the type is already frozen use the corresponding_record
2368 -- to check whether it is a proper descendant.
2371 (Is_Record_Type (Typ)
2372 and then Is_Concurrent_Type (Etype (N))
2373 and then Present (Corresponding_Record_Type (Etype (N)))
2374 and then Covers (Typ, Corresponding_Record_Type (Etype (N))))
2377 (Is_Concurrent_Type (Typ)
2378 and then Is_Record_Type (Etype (N))
2379 and then Present (Corresponding_Record_Type (Typ))
2380 and then Covers (Corresponding_Record_Type (Typ), Etype (N)))
2383 (not Is_Tagged_Type (Typ)
2384 and then Ekind (Typ) /= E_Anonymous_Access_Type
2385 and then Covers (Etype (N), Typ));
2390 Get_First_Interp (N, I, It);
2391 while Present (It.Typ) loop
2392 if (Covers (Typ, It.Typ)
2394 (Scope (It.Nam) /= Standard_Standard
2395 or else not Is_Invisible_Operator (N, Base_Type (Typ))))
2397 -- Ada 2005 (AI-345)
2400 (Is_Concurrent_Type (It.Typ)
2401 and then Present (Corresponding_Record_Type
2403 and then Covers (Typ, Corresponding_Record_Type
2406 or else (not Is_Tagged_Type (Typ)
2407 and then Ekind (Typ) /= E_Anonymous_Access_Type
2408 and then Covers (It.Typ, Typ))
2413 Get_Next_Interp (I, It);
2418 end Has_Compatible_Type;
2420 ---------------------
2421 -- Has_Abstract_Op --
2422 ---------------------
2424 function Has_Abstract_Op
2426 Typ : Entity_Id) return Entity_Id
2432 if Is_Overloaded (N) then
2433 Get_First_Interp (N, I, It);
2434 while Present (It.Nam) loop
2435 if Present (It.Abstract_Op)
2436 and then Etype (It.Abstract_Op) = Typ
2438 return It.Abstract_Op;
2441 Get_Next_Interp (I, It);
2446 end Has_Abstract_Op;
2452 function Hash (N : Node_Id) return Int is
2454 -- Nodes have a size that is power of two, so to select significant
2455 -- bits only we remove the low-order bits.
2457 return ((Int (N) / 2 ** 5) mod Header_Size);
2464 function Hides_Op (F : Entity_Id; Op : Entity_Id) return Boolean is
2465 Btyp : constant Entity_Id := Base_Type (Etype (First_Formal (F)));
2467 return Operator_Matches_Spec (Op, F)
2468 and then (In_Open_Scopes (Scope (F))
2469 or else Scope (F) = Scope (Btyp)
2470 or else (not In_Open_Scopes (Scope (Btyp))
2471 and then not In_Use (Btyp)
2472 and then not In_Use (Scope (Btyp))));
2475 ------------------------
2476 -- Init_Interp_Tables --
2477 ------------------------
2479 procedure Init_Interp_Tables is
2483 Headers := (others => No_Entry);
2484 end Init_Interp_Tables;
2486 -----------------------------------
2487 -- Interface_Present_In_Ancestor --
2488 -----------------------------------
2490 function Interface_Present_In_Ancestor
2492 Iface : Entity_Id) return Boolean
2494 Target_Typ : Entity_Id;
2495 Iface_Typ : Entity_Id;
2497 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean;
2498 -- Returns True if Typ or some ancestor of Typ implements Iface
2500 -------------------------------
2501 -- Iface_Present_In_Ancestor --
2502 -------------------------------
2504 function Iface_Present_In_Ancestor (Typ : Entity_Id) return Boolean is
2510 if Typ = Iface_Typ then
2514 -- Handle private types
2516 if Present (Full_View (Typ))
2517 and then not Is_Concurrent_Type (Full_View (Typ))
2519 E := Full_View (Typ);
2525 if Present (Interfaces (E))
2526 and then Present (Interfaces (E))
2527 and then not Is_Empty_Elmt_List (Interfaces (E))
2529 Elmt := First_Elmt (Interfaces (E));
2530 while Present (Elmt) loop
2533 if AI = Iface_Typ or else Is_Ancestor (Iface_Typ, AI) then
2541 exit when Etype (E) = E
2543 -- Handle private types
2545 or else (Present (Full_View (Etype (E)))
2546 and then Full_View (Etype (E)) = E);
2548 -- Check if the current type is a direct derivation of the
2551 if Etype (E) = Iface_Typ then
2555 -- Climb to the immediate ancestor handling private types
2557 if Present (Full_View (Etype (E))) then
2558 E := Full_View (Etype (E));
2565 end Iface_Present_In_Ancestor;
2567 -- Start of processing for Interface_Present_In_Ancestor
2570 -- Iface might be a class-wide subtype, so we have to apply Base_Type
2572 if Is_Class_Wide_Type (Iface) then
2573 Iface_Typ := Etype (Base_Type (Iface));
2580 Iface_Typ := Base_Type (Iface_Typ);
2582 if Is_Access_Type (Typ) then
2583 Target_Typ := Etype (Directly_Designated_Type (Typ));
2588 if Is_Concurrent_Record_Type (Target_Typ) then
2589 Target_Typ := Corresponding_Concurrent_Type (Target_Typ);
2592 Target_Typ := Base_Type (Target_Typ);
2594 -- In case of concurrent types we can't use the Corresponding Record_Typ
2595 -- to look for the interface because it is built by the expander (and
2596 -- hence it is not always available). For this reason we traverse the
2597 -- list of interfaces (available in the parent of the concurrent type)
2599 if Is_Concurrent_Type (Target_Typ) then
2600 if Present (Interface_List (Parent (Target_Typ))) then
2605 AI := First (Interface_List (Parent (Target_Typ)));
2607 -- The progenitor itself may be a subtype of an interface type.
2609 while Present (AI) loop
2610 if Etype (AI) = Iface_Typ
2611 or else Base_Type (Etype (AI)) = Iface_Typ
2615 elsif Present (Interfaces (Etype (AI)))
2616 and then Iface_Present_In_Ancestor (Etype (AI))
2629 if Is_Class_Wide_Type (Target_Typ) then
2630 Target_Typ := Etype (Target_Typ);
2633 if Ekind (Target_Typ) = E_Incomplete_Type then
2634 pragma Assert (Present (Non_Limited_View (Target_Typ)));
2635 Target_Typ := Non_Limited_View (Target_Typ);
2637 -- Protect the frontend against previously detected errors
2639 if Ekind (Target_Typ) = E_Incomplete_Type then
2644 return Iface_Present_In_Ancestor (Target_Typ);
2645 end Interface_Present_In_Ancestor;
2647 ---------------------
2648 -- Intersect_Types --
2649 ---------------------
2651 function Intersect_Types (L, R : Node_Id) return Entity_Id is
2652 Index : Interp_Index;
2656 function Check_Right_Argument (T : Entity_Id) return Entity_Id;
2657 -- Find interpretation of right arg that has type compatible with T
2659 --------------------------
2660 -- Check_Right_Argument --
2661 --------------------------
2663 function Check_Right_Argument (T : Entity_Id) return Entity_Id is
2664 Index : Interp_Index;
2669 if not Is_Overloaded (R) then
2670 return Specific_Type (T, Etype (R));
2673 Get_First_Interp (R, Index, It);
2675 T2 := Specific_Type (T, It.Typ);
2677 if T2 /= Any_Type then
2681 Get_Next_Interp (Index, It);
2682 exit when No (It.Typ);
2687 end Check_Right_Argument;
2689 -- Start of processing for Intersect_Types
2692 if Etype (L) = Any_Type or else Etype (R) = Any_Type then
2696 if not Is_Overloaded (L) then
2697 Typ := Check_Right_Argument (Etype (L));
2701 Get_First_Interp (L, Index, It);
2702 while Present (It.Typ) loop
2703 Typ := Check_Right_Argument (It.Typ);
2704 exit when Typ /= Any_Type;
2705 Get_Next_Interp (Index, It);
2710 -- If Typ is Any_Type, it means no compatible pair of types was found
2712 if Typ = Any_Type then
2713 if Nkind (Parent (L)) in N_Op then
2714 Error_Msg_N ("incompatible types for operator", Parent (L));
2716 elsif Nkind (Parent (L)) = N_Range then
2717 Error_Msg_N ("incompatible types given in constraint", Parent (L));
2719 -- Ada 2005 (AI-251): Complete the error notification
2721 elsif Is_Class_Wide_Type (Etype (R))
2722 and then Is_Interface (Etype (Class_Wide_Type (Etype (R))))
2724 Error_Msg_NE ("(Ada 2005) does not implement interface }",
2725 L, Etype (Class_Wide_Type (Etype (R))));
2727 Error_Msg_N ("incompatible types", Parent (L));
2732 end Intersect_Types;
2734 -----------------------
2735 -- In_Generic_Actual --
2736 -----------------------
2738 function In_Generic_Actual (Exp : Node_Id) return Boolean is
2739 Par : constant Node_Id := Parent (Exp);
2745 elsif Nkind (Par) in N_Declaration then
2746 if Nkind (Par) = N_Object_Declaration then
2747 return Present (Corresponding_Generic_Association (Par));
2752 elsif Nkind (Par) = N_Object_Renaming_Declaration then
2753 return Present (Corresponding_Generic_Association (Par));
2755 elsif Nkind (Par) in N_Statement_Other_Than_Procedure_Call then
2759 return In_Generic_Actual (Parent (Par));
2761 end In_Generic_Actual;
2767 function Is_Ancestor
2770 Use_Full_View : Boolean := False) return Boolean
2777 BT1 := Base_Type (T1);
2778 BT2 := Base_Type (T2);
2780 -- Handle underlying view of records with unknown discriminants using
2781 -- the original entity that motivated the construction of this
2782 -- underlying record view (see Build_Derived_Private_Type).
2784 if Is_Underlying_Record_View (BT1) then
2785 BT1 := Underlying_Record_View (BT1);
2788 if Is_Underlying_Record_View (BT2) then
2789 BT2 := Underlying_Record_View (BT2);
2795 -- The predicate must look past privacy
2797 elsif Is_Private_Type (T1)
2798 and then Present (Full_View (T1))
2799 and then BT2 = Base_Type (Full_View (T1))
2803 elsif Is_Private_Type (T2)
2804 and then Present (Full_View (T2))
2805 and then BT1 = Base_Type (Full_View (T2))
2810 -- Obtain the parent of the base type of T2 (use the full view if
2814 and then Is_Private_Type (BT2)
2815 and then Present (Full_View (BT2))
2817 -- No climbing needed if its full view is the root type
2819 if Full_View (BT2) = Root_Type (Full_View (BT2)) then
2823 Par := Etype (Full_View (BT2));
2830 -- If there was a error on the type declaration, do not recurse
2832 if Error_Posted (Par) then
2835 elsif BT1 = Base_Type (Par)
2836 or else (Is_Private_Type (T1)
2837 and then Present (Full_View (T1))
2838 and then Base_Type (Par) = Base_Type (Full_View (T1)))
2842 elsif Is_Private_Type (Par)
2843 and then Present (Full_View (Par))
2844 and then Full_View (Par) = BT1
2850 elsif Par = Root_Type (Par) then
2853 -- Continue climbing
2856 -- Use the full-view of private types (if allowed)
2859 and then Is_Private_Type (Par)
2860 and then Present (Full_View (Par))
2862 Par := Etype (Full_View (Par));
2871 ---------------------------
2872 -- Is_Invisible_Operator --
2873 ---------------------------
2875 function Is_Invisible_Operator
2877 T : Entity_Id) return Boolean
2879 Orig_Node : constant Node_Id := Original_Node (N);
2882 if Nkind (N) not in N_Op then
2885 elsif not Comes_From_Source (N) then
2888 elsif No (Universal_Interpretation (Right_Opnd (N))) then
2891 elsif Nkind (N) in N_Binary_Op
2892 and then No (Universal_Interpretation (Left_Opnd (N)))
2897 return Is_Numeric_Type (T)
2898 and then not In_Open_Scopes (Scope (T))
2899 and then not Is_Potentially_Use_Visible (T)
2900 and then not In_Use (T)
2901 and then not In_Use (Scope (T))
2903 (Nkind (Orig_Node) /= N_Function_Call
2904 or else Nkind (Name (Orig_Node)) /= N_Expanded_Name
2905 or else Entity (Prefix (Name (Orig_Node))) /= Scope (T))
2906 and then not In_Instance;
2908 end Is_Invisible_Operator;
2910 --------------------
2912 --------------------
2914 function Is_Progenitor
2916 Typ : Entity_Id) return Boolean
2919 return Implements_Interface (Typ, Iface, Exclude_Parents => True);
2926 function Is_Subtype_Of (T1 : Entity_Id; T2 : Entity_Id) return Boolean is
2930 S := Ancestor_Subtype (T1);
2931 while Present (S) loop
2935 S := Ancestor_Subtype (S);
2946 procedure List_Interps (Nam : Node_Id; Err : Node_Id) is
2947 Index : Interp_Index;
2951 Get_First_Interp (Nam, Index, It);
2952 while Present (It.Nam) loop
2953 if Scope (It.Nam) = Standard_Standard
2954 and then Scope (It.Typ) /= Standard_Standard
2956 Error_Msg_Sloc := Sloc (Parent (It.Typ));
2957 Error_Msg_NE ("\\& (inherited) declared#!", Err, It.Nam);
2960 Error_Msg_Sloc := Sloc (It.Nam);
2961 Error_Msg_NE ("\\& declared#!", Err, It.Nam);
2964 Get_Next_Interp (Index, It);
2972 procedure New_Interps (N : Node_Id) is
2976 All_Interp.Append (No_Interp);
2978 Map_Ptr := Headers (Hash (N));
2980 if Map_Ptr = No_Entry then
2982 -- Place new node at end of table
2984 Interp_Map.Increment_Last;
2985 Headers (Hash (N)) := Interp_Map.Last;
2988 -- Place node at end of chain, or locate its previous entry
2991 if Interp_Map.Table (Map_Ptr).Node = N then
2993 -- Node is already in the table, and is being rewritten.
2994 -- Start a new interp section, retain hash link.
2996 Interp_Map.Table (Map_Ptr).Node := N;
2997 Interp_Map.Table (Map_Ptr).Index := All_Interp.Last;
2998 Set_Is_Overloaded (N, True);
3002 exit when Interp_Map.Table (Map_Ptr).Next = No_Entry;
3003 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
3007 -- Chain the new node
3009 Interp_Map.Increment_Last;
3010 Interp_Map.Table (Map_Ptr).Next := Interp_Map.Last;
3013 Interp_Map.Table (Interp_Map.Last) := (N, All_Interp.Last, No_Entry);
3014 Set_Is_Overloaded (N, True);
3017 ---------------------------
3018 -- Operator_Matches_Spec --
3019 ---------------------------
3021 function Operator_Matches_Spec (Op, New_S : Entity_Id) return Boolean is
3022 Op_Name : constant Name_Id := Chars (Op);
3023 T : constant Entity_Id := Etype (New_S);
3031 -- To verify that a predefined operator matches a given signature,
3032 -- do a case analysis of the operator classes. Function can have one
3033 -- or two formals and must have the proper result type.
3035 New_F := First_Formal (New_S);
3036 Old_F := First_Formal (Op);
3038 while Present (New_F) and then Present (Old_F) loop
3040 Next_Formal (New_F);
3041 Next_Formal (Old_F);
3044 -- Definite mismatch if different number of parameters
3046 if Present (Old_F) or else Present (New_F) then
3052 T1 := Etype (First_Formal (New_S));
3054 if Nam_In (Op_Name, Name_Op_Subtract, Name_Op_Add, Name_Op_Abs) then
3055 return Base_Type (T1) = Base_Type (T)
3056 and then Is_Numeric_Type (T);
3058 elsif Op_Name = Name_Op_Not then
3059 return Base_Type (T1) = Base_Type (T)
3060 and then Valid_Boolean_Arg (Base_Type (T));
3069 T1 := Etype (First_Formal (New_S));
3070 T2 := Etype (Next_Formal (First_Formal (New_S)));
3072 if Nam_In (Op_Name, Name_Op_And, Name_Op_Or, Name_Op_Xor) then
3073 return Base_Type (T1) = Base_Type (T2)
3074 and then Base_Type (T1) = Base_Type (T)
3075 and then Valid_Boolean_Arg (Base_Type (T));
3077 elsif Nam_In (Op_Name, Name_Op_Eq, Name_Op_Ne) then
3078 return Base_Type (T1) = Base_Type (T2)
3079 and then not Is_Limited_Type (T1)
3080 and then Is_Boolean_Type (T);
3082 elsif Nam_In (Op_Name, Name_Op_Lt, Name_Op_Le,
3083 Name_Op_Gt, Name_Op_Ge)
3085 return Base_Type (T1) = Base_Type (T2)
3086 and then Valid_Comparison_Arg (T1)
3087 and then Is_Boolean_Type (T);
3089 elsif Nam_In (Op_Name, Name_Op_Add, Name_Op_Subtract) then
3090 return Base_Type (T1) = Base_Type (T2)
3091 and then Base_Type (T1) = Base_Type (T)
3092 and then Is_Numeric_Type (T);
3094 -- For division and multiplication, a user-defined function does not
3095 -- match the predefined universal_fixed operation, except in Ada 83.
3097 elsif Op_Name = Name_Op_Divide then
3098 return (Base_Type (T1) = Base_Type (T2)
3099 and then Base_Type (T1) = Base_Type (T)
3100 and then Is_Numeric_Type (T)
3101 and then (not Is_Fixed_Point_Type (T)
3102 or else Ada_Version = Ada_83))
3104 -- Mixed_Mode operations on fixed-point types
3106 or else (Base_Type (T1) = Base_Type (T)
3107 and then Base_Type (T2) = Base_Type (Standard_Integer)
3108 and then Is_Fixed_Point_Type (T))
3110 -- A user defined operator can also match (and hide) a mixed
3111 -- operation on universal literals.
3113 or else (Is_Integer_Type (T2)
3114 and then Is_Floating_Point_Type (T1)
3115 and then Base_Type (T1) = Base_Type (T));
3117 elsif Op_Name = Name_Op_Multiply then
3118 return (Base_Type (T1) = Base_Type (T2)
3119 and then Base_Type (T1) = Base_Type (T)
3120 and then Is_Numeric_Type (T)
3121 and then (not Is_Fixed_Point_Type (T)
3122 or else Ada_Version = Ada_83))
3124 -- Mixed_Mode operations on fixed-point types
3126 or else (Base_Type (T1) = Base_Type (T)
3127 and then Base_Type (T2) = Base_Type (Standard_Integer)
3128 and then Is_Fixed_Point_Type (T))
3130 or else (Base_Type (T2) = Base_Type (T)
3131 and then Base_Type (T1) = Base_Type (Standard_Integer)
3132 and then Is_Fixed_Point_Type (T))
3134 or else (Is_Integer_Type (T2)
3135 and then Is_Floating_Point_Type (T1)
3136 and then Base_Type (T1) = Base_Type (T))
3138 or else (Is_Integer_Type (T1)
3139 and then Is_Floating_Point_Type (T2)
3140 and then Base_Type (T2) = Base_Type (T));
3142 elsif Nam_In (Op_Name, Name_Op_Mod, Name_Op_Rem) then
3143 return Base_Type (T1) = Base_Type (T2)
3144 and then Base_Type (T1) = Base_Type (T)
3145 and then Is_Integer_Type (T);
3147 elsif Op_Name = Name_Op_Expon then
3148 return Base_Type (T1) = Base_Type (T)
3149 and then Is_Numeric_Type (T)
3150 and then Base_Type (T2) = Base_Type (Standard_Integer);
3152 elsif Op_Name = Name_Op_Concat then
3153 return Is_Array_Type (T)
3154 and then (Base_Type (T) = Base_Type (Etype (Op)))
3155 and then (Base_Type (T1) = Base_Type (T)
3157 Base_Type (T1) = Base_Type (Component_Type (T)))
3158 and then (Base_Type (T2) = Base_Type (T)
3160 Base_Type (T2) = Base_Type (Component_Type (T)));
3166 end Operator_Matches_Spec;
3172 procedure Remove_Interp (I : in out Interp_Index) is
3176 -- Find end of interp list and copy downward to erase the discarded one
3179 while Present (All_Interp.Table (II).Typ) loop
3183 for J in I + 1 .. II loop
3184 All_Interp.Table (J - 1) := All_Interp.Table (J);
3187 -- Back up interp index to insure that iterator will pick up next
3188 -- available interpretation.
3197 procedure Save_Interps (Old_N : Node_Id; New_N : Node_Id) is
3199 O_N : Node_Id := Old_N;
3202 if Is_Overloaded (Old_N) then
3203 Set_Is_Overloaded (New_N);
3205 if Nkind (Old_N) = N_Selected_Component
3206 and then Is_Overloaded (Selector_Name (Old_N))
3208 O_N := Selector_Name (Old_N);
3211 Map_Ptr := Headers (Hash (O_N));
3213 while Interp_Map.Table (Map_Ptr).Node /= O_N loop
3214 Map_Ptr := Interp_Map.Table (Map_Ptr).Next;
3215 pragma Assert (Map_Ptr /= No_Entry);
3218 New_Interps (New_N);
3219 Interp_Map.Table (Interp_Map.Last).Index :=
3220 Interp_Map.Table (Map_Ptr).Index;
3228 function Specific_Type (Typ_1, Typ_2 : Entity_Id) return Entity_Id is
3229 T1 : constant Entity_Id := Available_View (Typ_1);
3230 T2 : constant Entity_Id := Available_View (Typ_2);
3231 B1 : constant Entity_Id := Base_Type (T1);
3232 B2 : constant Entity_Id := Base_Type (T2);
3234 function Is_Remote_Access (T : Entity_Id) return Boolean;
3235 -- Check whether T is the equivalent type of a remote access type.
3236 -- If distribution is enabled, T is a legal context for Null.
3238 ----------------------
3239 -- Is_Remote_Access --
3240 ----------------------
3242 function Is_Remote_Access (T : Entity_Id) return Boolean is
3244 return Is_Record_Type (T)
3245 and then (Is_Remote_Call_Interface (T)
3246 or else Is_Remote_Types (T))
3247 and then Present (Corresponding_Remote_Type (T))
3248 and then Is_Access_Type (Corresponding_Remote_Type (T));
3249 end Is_Remote_Access;
3251 -- Start of processing for Specific_Type
3254 if T1 = Any_Type or else T2 = Any_Type then
3261 elsif (T1 = Universal_Integer and then Is_Integer_Type (T2))
3262 or else (T1 = Universal_Real and then Is_Real_Type (T2))
3263 or else (T1 = Universal_Fixed and then Is_Fixed_Point_Type (T2))
3264 or else (T1 = Any_Fixed and then Is_Fixed_Point_Type (T2))
3268 elsif (T2 = Universal_Integer and then Is_Integer_Type (T1))
3269 or else (T2 = Universal_Real and then Is_Real_Type (T1))
3270 or else (T2 = Universal_Fixed and then Is_Fixed_Point_Type (T1))
3271 or else (T2 = Any_Fixed and then Is_Fixed_Point_Type (T1))
3275 elsif T2 = Any_String and then Is_String_Type (T1) then
3278 elsif T1 = Any_String and then Is_String_Type (T2) then
3281 elsif T2 = Any_Character and then Is_Character_Type (T1) then
3284 elsif T1 = Any_Character and then Is_Character_Type (T2) then
3287 elsif T1 = Any_Access
3288 and then (Is_Access_Type (T2) or else Is_Remote_Access (T2))
3292 elsif T2 = Any_Access
3293 and then (Is_Access_Type (T1) or else Is_Remote_Access (T1))
3297 -- In an instance, the specific type may have a private view. Use full
3298 -- view to check legality.
3300 elsif T2 = Any_Access
3301 and then Is_Private_Type (T1)
3302 and then Present (Full_View (T1))
3303 and then Is_Access_Type (Full_View (T1))
3304 and then In_Instance
3308 elsif T2 = Any_Composite and then Is_Aggregate_Type (T1) then
3311 elsif T1 = Any_Composite and then Is_Aggregate_Type (T2) then
3314 elsif T1 = Any_Modular and then Is_Modular_Integer_Type (T2) then
3317 elsif T2 = Any_Modular and then Is_Modular_Integer_Type (T1) then
3320 -- ----------------------------------------------------------
3321 -- Special cases for equality operators (all other predefined
3322 -- operators can never apply to tagged types)
3323 -- ----------------------------------------------------------
3325 -- Ada 2005 (AI-251): T1 and T2 are class-wide types, and T2 is an
3328 elsif Is_Class_Wide_Type (T1)
3329 and then Is_Class_Wide_Type (T2)
3330 and then Is_Interface (Etype (T2))
3334 -- Ada 2005 (AI-251): T1 is a concrete type that implements the
3335 -- class-wide interface T2
3337 elsif Is_Class_Wide_Type (T2)
3338 and then Is_Interface (Etype (T2))
3339 and then Interface_Present_In_Ancestor (Typ => T1,
3340 Iface => Etype (T2))
3344 elsif Is_Class_Wide_Type (T1)
3345 and then Is_Ancestor (Root_Type (T1), T2)
3349 elsif Is_Class_Wide_Type (T2)
3350 and then Is_Ancestor (Root_Type (T2), T1)
3354 elsif Ekind_In (B1, E_Access_Subprogram_Type,
3355 E_Access_Protected_Subprogram_Type)
3356 and then Ekind (Designated_Type (B1)) /= E_Subprogram_Type
3357 and then Is_Access_Type (T2)
3361 elsif Ekind_In (B2, E_Access_Subprogram_Type,
3362 E_Access_Protected_Subprogram_Type)
3363 and then Ekind (Designated_Type (B2)) /= E_Subprogram_Type
3364 and then Is_Access_Type (T1)
3368 elsif Ekind_In (T1, E_Allocator_Type,
3369 E_Access_Attribute_Type,
3370 E_Anonymous_Access_Type)
3371 and then Is_Access_Type (T2)
3375 elsif Ekind_In (T2, E_Allocator_Type,
3376 E_Access_Attribute_Type,
3377 E_Anonymous_Access_Type)
3378 and then Is_Access_Type (T1)
3382 -- If none of the above cases applies, types are not compatible
3389 ---------------------
3390 -- Set_Abstract_Op --
3391 ---------------------
3393 procedure Set_Abstract_Op (I : Interp_Index; V : Entity_Id) is
3395 All_Interp.Table (I).Abstract_Op := V;
3396 end Set_Abstract_Op;
3398 -----------------------
3399 -- Valid_Boolean_Arg --
3400 -----------------------
3402 -- In addition to booleans and arrays of booleans, we must include
3403 -- aggregates as valid boolean arguments, because in the first pass of
3404 -- resolution their components are not examined. If it turns out not to be
3405 -- an aggregate of booleans, this will be diagnosed in Resolve.
3406 -- Any_Composite must be checked for prior to the array type checks because
3407 -- Any_Composite does not have any associated indexes.
3409 function Valid_Boolean_Arg (T : Entity_Id) return Boolean is
3411 if Is_Boolean_Type (T)
3412 or else Is_Modular_Integer_Type (T)
3413 or else T = Universal_Integer
3414 or else T = Any_Composite
3418 elsif Is_Array_Type (T)
3419 and then T /= Any_String
3420 and then Number_Dimensions (T) = 1
3421 and then Is_Boolean_Type (Component_Type (T))
3423 ((not Is_Private_Composite (T) and then not Is_Limited_Composite (T))
3425 or else Available_Full_View_Of_Component (T))
3432 end Valid_Boolean_Arg;
3434 --------------------------
3435 -- Valid_Comparison_Arg --
3436 --------------------------
3438 function Valid_Comparison_Arg (T : Entity_Id) return Boolean is
3441 if T = Any_Composite then
3444 elsif Is_Discrete_Type (T)
3445 or else Is_Real_Type (T)
3449 elsif Is_Array_Type (T)
3450 and then Number_Dimensions (T) = 1
3451 and then Is_Discrete_Type (Component_Type (T))
3452 and then (not Is_Private_Composite (T) or else In_Instance)
3453 and then (not Is_Limited_Composite (T) or else In_Instance)
3457 elsif Is_Array_Type (T)
3458 and then Number_Dimensions (T) = 1
3459 and then Is_Discrete_Type (Component_Type (T))
3460 and then Available_Full_View_Of_Component (T)
3464 elsif Is_String_Type (T) then
3469 end Valid_Comparison_Arg;
3475 procedure Write_Interp (It : Interp) is
3477 Write_Str ("Nam: ");
3478 Print_Tree_Node (It.Nam);
3479 Write_Str ("Typ: ");
3480 Print_Tree_Node (It.Typ);
3481 Write_Str ("Abstract_Op: ");
3482 Print_Tree_Node (It.Abstract_Op);
3485 ----------------------
3486 -- Write_Interp_Ref --
3487 ----------------------
3489 procedure Write_Interp_Ref (Map_Ptr : Int) is
3491 Write_Str (" Node: ");
3492 Write_Int (Int (Interp_Map.Table (Map_Ptr).Node));
3493 Write_Str (" Index: ");
3494 Write_Int (Int (Interp_Map.Table (Map_Ptr).Index));
3495 Write_Str (" Next: ");
3496 Write_Int (Interp_Map.Table (Map_Ptr).Next);
3498 end Write_Interp_Ref;
3500 ---------------------
3501 -- Write_Overloads --
3502 ---------------------
3504 procedure Write_Overloads (N : Node_Id) is
3510 Write_Str ("Overloads: ");
3511 Print_Node_Briefly (N);
3513 if not Is_Overloaded (N) then
3514 Write_Line ("Non-overloaded entity ");
3515 Write_Entity_Info (Entity (N), " ");
3517 elsif Nkind (N) not in N_Has_Entity then
3518 Get_First_Interp (N, I, It);
3519 while Present (It.Nam) loop
3520 Write_Int (Int (It.Typ));
3522 Write_Name (Chars (It.Typ));
3524 Get_Next_Interp (I, It);
3528 Get_First_Interp (N, I, It);
3529 Write_Line ("Overloaded entity ");
3530 Write_Line (" Name Type Abstract Op");
3531 Write_Line ("===============================================");
3534 while Present (Nam) loop
3535 Write_Int (Int (Nam));
3537 Write_Name (Chars (Nam));
3539 Write_Int (Int (It.Typ));
3541 Write_Name (Chars (It.Typ));
3543 if Present (It.Abstract_Op) then
3545 Write_Int (Int (It.Abstract_Op));
3547 Write_Name (Chars (It.Abstract_Op));
3551 Get_Next_Interp (I, It);
3555 end Write_Overloads;